1. Technical Field
The present invention relates to dump trailers on trucks. More particularly the present invention relates to dump trailers which are pivotally mounted such that the front may be elevated so that a load carried in the trailer is removed by gravity through a chute located in a rear tailgate wall. Specifically, the present invention relates to a center door assembly for a dump trailer chute which includes a locking assembly configured to selectively lock a door of the assembly in each of an open position and a closed position.
2. Background Information
Many trucks have a bed, trailer, or body that is lifted upwardly relative to the vehicle to unload materials by gravity from within the bed. Dump trailers for industrial use, such as dump trucks and coal trucks, typically employ a tailgate which is pivotally mounted to the top of the side walls of the dump body and extends across the width of the bed, such that it may swing between an open and closed position as the front of the dump body varies in elevation.
These rear tailgates oftentimes include a center door assembly called a “coal chute”. The coal chute is substantially narrower than the rear tailgate and includes a door that can be selectively opened or closed. Common coal chute designs involve sliding the door up and down within tracks mounted in the sidewalls of the chute. Using a pivot arm, the user draws the door upwards along the chute door track before the bed of the dump truck is lifted. As the bed is lifted, the material within the bed exits through the coal chute in a contained and controlled stream that can be fed directly onto a ditch, intake basin, or onto a conveyor belt.
An examination of the prior art reveals that general center door assemblies for dump trailers exist. U.S. Pat. No. 8,042,875 issued in the name of the same inventor as this application, James A. Maiorana, provides a retractable center door assembly for a dump trailer operable by rotating a crank arm attached to a pivot linkage assembly to move the door between a closed and open position. The '875 Patent can secure the door in an open position by turning a handle, however the door may sometimes become unlocked and slide down during unloading or may sometimes become inadvertently stuck.
Therefore, the need continues to exist in the art for an improved center door assembly for a dump trailer, the present invention addresses some of these issues.